[请教]BIOS地址映射?

暴雪

原512K的ROM，现换了一个1M的ROM，windows下在 0xFFF0 0000~0xFFF7 FFFF 可以看到追加的512K的内容。
但在启动计算机时(BIOS没有初始化计算机），无法访问追加的512K的ROM。
5 n, I- Z' U- K) Q0 [( u(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)

) O2 d2 B+ L% P- V8 u+ A我的计算机用的是intel的ICH7南桥。
在手册上
FWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
1 ?! E# X9 ]5 p2 i4 fFWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
The IDSEL programmed in this field addresses the following memory ranges:
- p3 U$ Q5 y/ z# f& CFF70 0000h – FF7F FFFFh
" k9 I: k8 T% j3 W. l5 GFF30 0000h – FF3F FFFFh
4 g& t7 C% R6 w9 p' U在这里 IDSEL 如何理解。
FWH_DEC_EN1—Firmware Hub Decode Enable Register
(LPC I/F—D31:F0)
FWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
7 B' B% g1 Z+ B; _. x0 = Disable.
; h* ?+ _6 f' i( m, j. ]# V' j1 = Enable the following ranges for the Firmware Hub
FF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
5 H/ A! F& m$ O8 f- K' u除了上面的数据区域，还有其它的数据区域控制ROM到内存地址的映射吗？
. ]! _3 J" q4 C0 b
# j, T7 H' y3 T/ Z( [' V2 C' E& r4 H谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
This one clock field is used to indicate which of multiple Firmware components is being selected.
The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
pins on the Firmware component. If there is a match, the Firmware component will continue to
+ }. G0 h6 Q+ `6 ?decode the cycle to determine which bytes are requested on a read or which bytes to update on a
write. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
% q( J8 \' j$ K; _0 r2 v! Ca standby power state.
3 _6 f' ^; ?% K, O" c
详见LPC spec:
; ]7 g: F" Q' C& q- }: {http://www.intel.com/design/chipsets/industry/25128901.pdf
# V5 M4 e/ }* M+ X6 m0 f* d
在ICH 7 中似乎就这几个吧(FWH_SEL1,FWH_SEL2,FWH_DEC_EN1,BIOS_CNTL),据我现在知道的.